Valve for rock drills



Feb. 21, 1933. G. w. HULSHIZER VALVE FOR ROCK DRILLS Filed Feb. 15, 1930 INVENTOR. G601 eldlfuldfizjea 4 4' I115 ATTORNEY.

Patented Feb. 21, 1933 UNITED STATES PATENT OFFICE GEORGE W. HULSHIZER, OF STEWARTSVILLE, NEW JERSEY, ASSIGNOR TO INGERSOLL- RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY VALVE FOE ROCK DRILLS Application filed February 15, 1930. Serial No. 428,759.

This invention relates to rock drills, but

more particularly to a distributing valve for fluid actuated rock drills of the hammer type.

The objects of the invention are to obtain a rapid and positive action of'the valve and to obtain a maximum amount of work from the drill with a minimum expenditure of pressure fluid. 7

Other objects will be in part obvious and in part pointed out hereinafter.

In the accompanying drawin illustrating the invention and in which similar reference characters refer to similarparts,

Figure 1 is a sectional elevation of a rock drill equipped with a valve constructed in accordance with the practice of the invention and showing the valve in position to admit pressure fluid into'the piston chamber for actuating the piston on its working stroke, and

Figure 2 is a similar view showing the valve in position for admitting pressure fluid to the piston chamber for returning the piston.

Referring more I particularly to the draw ing, A designates a rock drill comprising acylinder B having a piston chamber G to ac commodate a reciprocatory hammer piston D. The cylinder B in this instance has a free exhaust port E which is controlled by the piston D. Y e

The valve mechanism constructed in accordance with the practice of the invention is designated generally by F and is, for illustrative purposes, arranged in the rear end of the cylinder B. The valve mechanism-may, as shown, also extend into a back head G which is in this instance seated on the rear end of the cylinder B to form aclosure therefor.

The back head G may be secured tothe cylinder B in any suitable manner, as for instance, by the usual side bolts (not shown) 7 and forms a housing for a throttle valve H whereby the admission of pressure fluid into the drill A may be controlled. The throttle valve H may be of the rotary type having a central chamber J into which pressure fluid may be constantly admitted from a source of supply. In the wall of the throttle v valve H is a port K through which pressure fluid may flow-to a supply passage L in the back head a The valve mechanism comprises a block 0 which forms a valve chest having an en larged head Pwhich lies in the rear end of the cylinder B and a reduced portionv Q, which extends into the back head G. The head P may seat (upon a back cylinder washer Q which forms a closure for the rear end of the piston. chamber C and also acts as .an end wall for a valve chamber R inthe block 0.

The valve chamber R, which in shape resembles that of the block 0, comprises an enlarged portion S which is located in the head P of the block 0 and a reduced portion T which extends rearwardly through the reduced portion Q of the block 0. i

The'pressure fluid intended to be distributed to the ends of the piston chamber C is supplied to the .valve chamber R by the supply passage L and a port U in the head P of the'block 0 through which pressure fluid flows to the rear end of the valve chamber R. Such pressure fluid flows from the valve chamber R to the front end of the sage V which opens at one end into the front end of the piston chamber C and communicates at its inlet opening or port W with an annular recess X in the valve block 0, the recess X being preferably located atthe juncture of the enlarged and reduced portions S and T respectively of the valve chamber R; The pressure fluid utilized for actuating the piston D forwardly on its working stroke isadmitted into the rear end of the piston chamber C through an inlet passage Y in the back cylinder washer Q.

Disposed within the valve chamber R for controlling the distribution. of pressure fluid to the inlet passages V and Y is a distributing Valve Z which comprises a stem 1) arranged slidably within thereduced portion T of the valve chamber, and a flange 0 at the front end of the valve which lies within the enlarged portion Sof the, valve chamberR. The valve Z may be provided with Similarly, on the rear end of the flange 0 is an opposing pressure area 9 which is also constantly exposed to pressure fluid tending to throw the valve Z forwardly. The pressure area 9 is, however, of somewhat smaller area than the pressure area so that in the absence of other forces acting .against the valve Z the pressure acting against the area f will predominate over that actlng against the area g.

Additional means are provided to assist in actuating the valve from one limiting position to the other. is provided with a cavity h in its front end and an endsurface j of said cavity, together with the end surface is of the recess d, constitute actuating surfaces against .which compression created in'the rear end of the piston chamber C by the piston D may act to assist the pressure fluid acting against the pressurearea f to throw the valve Z rearwardly.

In the rear end of the flange c is a shoulder Q having an actuating surface 79 on its rear end which, in one position of the valve Z, extends into the annular recess X and against which compression created in the front end of the piston chamber 0 may act to augment the pressure acting against the pressure area 9" for throwing the valve Z forwardly. V

The shoulder 0, as will be'observed, enters the recess X before the valve Z reaches its rearmost limiting position in order to effect an early out off from the front end of the piston chamber C. This isd'esirable since it enables the supply of pressure fluid to the front end of the piston chamber 0 to be cut off before the piston D uncovers the exhaust port E during the rearward stroke of the piston. The pressure fluid acting against the front end of the piston D may then act expansively during a portion of the'rearward stroke to return the piston.

The valve Z is provided with an annular seating surface 9 which encircles the shoulder 0 and is adapted to seat against an annular flange r in the. rear end of the enlarged portion S of the valve chamber to limit the rearward'movement of the valve Z. The seating surface 9 constitutes in this instance a holding surface which is intermittently exposed to pressure fluid flowing thereover to assist in holding the valve To this end the valve momentarily stationary in the front end of the valve chamber during the time pressure fluid is being admitted through the inlet passage V into the front end of the piston chamber C.

For. the best operation of the vvalve the reduced portion T of the valve chamber may be provided with an atmospheric vent s to prevent the accumulation of pressure fluid rearwardly of the stem 6 of the valve.

will of course be exposed to pressure fluid.

At the same time, however, the entire front area or surface of the valve will also be exposed to pressure fluid so that the valve will be held immovable in its rearmost position.

When the piston D uncovers the exhaust port E the pressure fluid in the rear end'of the piston chamber 0 will exhaust to the atmosphere. This will cause a drop in pressure in the-front end of the enlarged portion S of the valve chamber. As the piston D continues forwardly, the air in the front end of the piston chamber will be compressed. Such compression will act against the actuating surface 7) and will, together with the pressure acting against the pressure area 9, throw the valve D forwardly to close the inlet passage Y. This movement of the valve will take place immedi ately after the exhaust port E is uncovered and also at about the instant the hammer piston D delivers its blow to the working implement intended to be actuated.

In the new position of the valve Z pressure fluid will flow from the rear end of the enlarged portion S of the valve chamber across the surfaces 9, p and 9 into and through the inlet passage V to the front end of the piston chamber. The piston D will then be returned to its initial position. The valve will be held in its foremost position by the pressure fluid acting against the rear surfaces of the flange 0 and the shoulder 0 until the piston gains suflicient moment-um to carry it to its rearmost limiting position.

During the rearward travel of the piston D and after the piston uncovers the exhaust port E, the air in the rear end of the piston chamber C will be compressed. This compression will then act against the surfaces j and 7e and together with the live pressure fluid acting against the pressure area f will start the valve Z rearwardly.

Shortly after the valve Z has been unseated, the shoulder 0 will enter the annular recess X and Will thus cut off the flow of pressure fluid to the front end of the piston chamber before the seating surface 9 reaches its seat 1". The shoulder 0 will enter the recess X before the exhaust port E is uncovered by the piston D. The piston D however Will continue rearwardly and will uncover the exhaust port E so that the pressure fluid in the front end of the piston chamber C may exhaust to the atmosphere.

I claim:

In a fluid actuated rock drill, the combination of a cylinder having a piston chamber and a piston in the piston chamber, an exhaust port in the cylinder, a valve chest having a valve chamber, inlet passages leading from the valve chamber to the piston chamber, a distributing valve in the valve chamber comprising a stem and a flange guided by the Wall of the valve chamber, passages in the flange through which pressure fluid flows to the rear end of the piston chamber, a pressure area on the rear end of the flange against which pressure fluid constantly acts tending to throw the valve for admitting pressure fluid to the front end of the cylinder, a pressure area at the front end of the flange of larger area than the first mentioned pressure area and being constantly exposed to pressure fluid tending to throw the valve for admitting pressure fluid to the rear end of the piston chamber, an actuating surface on the valve intermittently exposed to compression to augment the pressure acting against the first mentioned pressure area for throwing the valve, a holding surface on the rear end of the flange intermittently exposed to pressure fluid to assist the pressure fluid acting against the first mentioned pressure area and the actuating surface in holding the valve momentarily stationary, an actuating surface on the front end of the valve intermittently exposed to compression to augment the pressure fluid acting against the second mentioned pressure area for throwing the valve, and a shoulder on the valve to cut-off the admission of pressure fluid to the front end of the piston chamber before the piston uncovers the exhaust port.

In testimony whereof I have signed this specification.

GEORGE W. HULSHIZER. 

